Fungal mycobiome as probiotics, diagnostics and therapeutics

ABSTRACT

The present invention relates to methods of using fungal mycobiome as a means of treating and/or diagnosing diseases in a subject. In one embodiment, the present invention provides a method of diagnosing inflammatory bowel disease based on the composition of fungal strains present in the gut of a subject, and treating the subject by administering a probiotic biotherapy. In another embodiment, the present invention provides a method of diagnosing a severe form of ulcerative colitis by detecting the presence of a deficiency in dectin-1 expression in  s. fibuligera  in the gut of a subject.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Phase of International ApplicationPCT/US2013/038466, filed Apr. 26, 2013, which designated the U.S. andthat International Application was published under PCT Article 21(2) inEnglish. This application also claims priority under 35 U.S.C. §119(e)to U.S. Provisional Application No. 61/639,306 filed Apr. 27, 2012,which is hereby incorporated by reference in its entirety.

This invention was made with Government support under Grant No. AI071116awarded by the National Institutes of Health. The Government has certainrights in the invention.

BACKGROUND

All publications herein are incorporated by reference to the same extentas if each individual publication or patent application was specificallyand individually indicated to be incorporated by reference. Thefollowing description includes information that may be useful inunderstanding the present invention. It is not an admission that any ofthe information provided herein is prior art or relevant to thepresently claimed invention, or that any publication specifically orimplicitly referenced is prior art.

Interactions between the commensal microflora and the gut immune systemare critical for establishing a proper balance between immune hostdefense mechanisms and tissue health. Changes in gut bacteriacomposition described as “disbiosis” have been associated withintestinal inflammation and metabolic syndrome. The vast majority ofstudies on the interaction between commensal microbiota and the hosthave focused on gut bacteria, and the terms “intestinal microbiota” and“intestinal bacteria” are often used interchangeably. However, recentstudies have begun to note that a fraction of mucosa-associatedmicroorganisms are not bacterial. For example, commensal viruses cantrigger gut inflammation by targeting host Paneth cells or indirectly bytargeting commensal bacteria. Although a few studies have suggested thepresence of commensal fungi in the gut, it is unknown whether theyinteract with the mucosal immune system or influence disease. Asillustrated recently by Segmented Filamentous Bacteria (SFB) andClostridium sp., even organisms representing a proportionally smallfraction of the total microbiome can have profound effects on the hostimmune system. Thus it is important to evaluate whether gut fungisignificantly influence the maintenance of host intestinal homeostasis.

Fungi are recognized by a number of immune receptors among whichDectin-1 has emerged as key for recognition, phagocytosis, and killingby myeloid phagocytes. Dectin-1 is a C-type lectin receptor thatrecognizes β-1,3-glucans found in the cell walls of nearly all fungi.Dectin-1 activates intracellular signals through CARD9 leading toinflammatory cytokine production and enhanced induction of Th17 immuneresponses. Deficiencies in either Dectin-1 or CARD9 result in enhancedsusceptibility to pathogenic fungal infections in humans and mice.Polymorphic variants in the gene for CARD9 are strongly associated withCrohn's disease and ulcerative colitis in humans. Furthermore,anti-Saccharomyces cerevisiae antibodies (ASCA) against yeast mannanhave been strongly associated with Crohn's disease. Together, theselater findings suggest a possible link between immune responses tocommensal fungi and intestinal disease.

SUMMARY OF THE INVENTION

Various embodiments include a method of treating an inflammatory boweldisease (IBD) in a subject, comprising providing a composition of a gutfungi, and administering a therapeutically effective dosage of thecomposition to the subject. In another embodiment, the IBD is ulcerativecolitis. In another embodiment, the gut fungi is saccharomycopsis. Inanother embodiment, the gut fungi is saccharomycopsis fibuligera. Inanother embodiment, the subject is human. In another embodiment, thesubject is a rodent. In another embodiment, the IBD is a severe form ofulcerative colitis. In another embodiment, the composition of a gutfungi is a probiotic biotherapy.

Other embodiments include a method of diagnosing susceptibility to adisease in a subject, comprising obtaining a sample from the individual,subjecting the sample to a genotyping assay adapted to determine thepresence or absence of one or more risk variants at the Dectin-1 gene(CLEC7A), and diagnosing susceptibility to the disease in the individualbased on the presence of one or more risk variants at the Dectin-1 gene(CLEC7A). In another embodiment, the disease is an inflammatory disease.In another embodiment, the disease is inflammatory bowel disease (IBD).In another embodiment, the disease is a severe form of ulcerativecolitis. In another embodiment, the disease is based on the inability tocontrol fungi in the gut of the individual.

Other embodiments include a method of diagnosing a disease in a subject,comprising obtaining a sample from the gut of the subject, assaying thesample to determine a composition of gut fungi strain, diagnosing thedisease based on the composition of gut fungi strain in the subject. Inanother embodiment, the composition of gut fungi strain comprisessaccharomycopsis fibuligera. In another embodiment, the saccharomycopsisfibuligera is characterized by an absence of functioning Dectin-1. Inanother embodiment, the subject is human. In another embodiment, thedisease is a severe form of ulcerative colitis. In another embodiment,the disease is an inflammatory disease.

Various embodiments include a probiotic, comprising a composition of gutfungi comprising saccharomycopsis. In another embodiment, thecomposition comprises saccharomycopsis fibuligera.

Other embodiments include a method of treating a disease in a subject,comprising diagnosing a disease based on a composition of gut fungistrain present in the subject, and treating the subject. In anotherembodiment, treating the subject comprises administering a probioticbiotherapy. In another embodiment, the disease is inflammatory boweldisease (IBD).

Other features and advantages of the invention will become apparent fromthe following detailed description, taken in conjunction with theaccompanying drawings, which illustrate, by way of example, variousembodiments of the invention.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 depicts, in accordance with an embodiment herein, commensal fungiare present in the intestine and are recognized by Dectin-1. (A)Prevalence of fungi in mucosa isolated from ileum, caecum, proximal(prox) and distal (dist) colon of C57BL/6J mice. ITS1-2 rDNA level wasanalyzed by qPCR and normalized to β-actin DNA. (B), (C) Visualizationof commensal fungi in the intestine. Colon sections were stained with(B) anti-fungal antibody or with (C) a soluble Dectin-1 probe (sDEC-1)and counterstained with DAPI. Lower panels in (C) show that DAPI-stainedbacteria and fungi are in close proximity to each other. (D) Intestinalfungi are recognized by Dectin-1. Fecal pellets were homogenized andlabeled with sDEC-1 in presence (gray histogram) or absence (blackhistogram) of laminarin (a soluble β-glucan) to block specific binding.Binding was assessed by flow cytometry (left panels). Dectin-1-bindingfungi were sorted (right panels) and visualized by confocal microscopy.(E) Intestinal fungi are present in the gut of different mammals. Feceswere analyzed for fungal 18S rDNA by qPCR. (F) ASCA generation after DSScolitis. Mice were exposed twice to 2.5% DSS-supplemented water for 7days each separated by two weeks of recovery. Serum samples werecollected before DSS treatment (day 0) and 2 weeks after the last DSScycle (42 days total) and ASCA IgM and IgG were measured by ELISA. Eachsymbol represents a mouse, all error bars indicate the s.d. *P<0.05;unpaired t test. All data are representative of at least two independentexperiments with similar results.

FIG. 2 depicts, in accordance with an embodiment herein, dectin-1regulates severity of colitis. Wild type (WT) and Clec7a−/− littermateswere treated with 2.5% DSS for 7 days and kept on water for 4 additionaldays. Colitis progress and severity were assessed by measuring bodyweight during treatment (A) and histology (B, D), and TNF-α productionin the colon (C) on day 11. (E) Dot plots show the percentage of IL-17and IFN-γ producing CD4+ T cells isolated from large intestine laminapropria (LI-LP) and mesenteric lymph nodes (MLN) on day 11. (F) LI-LPand MLN cells were cultured with antibodies against CD3 and CD28. Theproduction of IL-17 and IFN-γ was measured by ELISA. Microbiota fromClec7a−/− mice do not transfer disease to the WT. (G), (H) WT andClec7a−/− mice were given an antibiotic cocktail for 3 weeks,transplanted as indicated (red) with fecal microflora from WT orClec7a−/− mice and treated with DSS as in (A). Disease severity wasaccessed by histology score (G) and by cytokine production byanti-CD3/anti-CD28 stimulated LI-LP and MLN T cells (H). Each symbolrepresents a different mouse. One of four independent experiments isshown. Error bars, s.d., * P<0.05, ** P<0.01 FIG. 3 depicts, inaccordance with an embodiment herein, defining the fungal microbiome andcharacterizing the specific role of Dectin-1-mediated host defenseduring colitis (A) DNA was isolated from murine feces and fungalmicrobiome analysis was performed using Roche 454 and Illumina GAsequencing of ITS1-2 rDNA. The taxonomic distribution of the mostabundant fungal genera is shown (large pie chart), and species breakdownfor major groups are provided (small pie charts). (B) Quantitativeanalysis of the major intestinal fungal genera in wild type andClec7a−/− mice before and after treatment with DSS. Illumina GA datawere analyzed and presented as relative percentage of dominant fungalgenera (n=16 mice). (C) Fungal invasion of colonic tissue in Clec7a−/−mice during colitis. Colon sections from WT and Clec7a−/− mice beforeand after colitis were stained with the sDEC-1 probe and counterstainedwith DAPI. (D) Reduced anti-fungal killing activity by intestinallyconditioned Clec7a−/− dendritic cells. Intestinally conditioneddendritic cells were incubated with live C. tropicalis and killing wasassessed after 6 and 18 hours. (E, F, G) WT and Clec7a−/− mice weresupplemented with four doses of C. tropicalis or S. fibuligera everyother day, and then treated with 2.5% DSS for 7 days and kept on waterfor 4 additional days. Histology score (E) and the production of IL-17and IFN-γ by MLN cells (F) were determined 4 days after DSS treatment.(G) The presence of C. tropicalis was analyzed by qPCR after DSStreatment. Data are representative of at least two independentexperiments with similar results. Error bars, s.d., * P<0.05, ** P<0.01.

FIG. 4 depicts, in accordance with an embodiment herein, anti-fungaltherapy ameliorates colitis in Clec7a−/− mice and CLEC7A associates withulcerative colitis severity in humans. (A) WT and Clec7a−/− mice weregiven fluconazole in their drinking water for total of 14 days (starting2 days prior the induction of DSS colitis), and body weight wasmeasured. Fluconazole significantly abrogated weight loss in Clec7a−/−mice from day 9 (p<0.05). Histology score (B), the percentage of IL-17and IFN-γ producing CD4+ T cells in LI-LP (C), and IL-17 and IFN-γproduction in MLNs (D) were determined 4 days after the 7 days of DSStreatment. Each symbol represents a different mouse. One of threeindependent experiments with similar results is shown. Error bars,s.d., * P<0.05, ** P<0.01. (E) Specific CLEC7A haplotypes associate withmedically refractory ulcerative colitis (MRUC). Haplotypes were formedfrom rs2078178 and rs16910631 using PHASE v2.3. Haplotypes listed as“Other Combinations” were those that could not be reliably determined(posterior p<0.95). (F) The CLEC7A “AG/AG” haplotype associates withseverity of disease as indicated by earlier progression to colectomy.Haplotypes were tested for association with time to surgery by fittingthe MRUC/non-MRUC and time-to surgery with a Cox proportional hazardsmodel.

FIG. 5 depicts, in accordance with an embodiment herein, commensal fungiare present in the intestine of 129S2/Sv mice.

(A) Mucosa was isolated from ileum, caecum, proximal and distal colon of129S2/Sv mice; ITS1-2 rDNA level was analyzed by qPCR and normalized tofi-actin DNA.

FIG. 6 depicts, in accordance with an embodiment herein, solubleβ-glucan blocks binding of Dectin-1 to intestinal fungi. Colon sectionswere stained with a soluble Dectin-1 probe (sDEC-1) in the presence orabsence of soluble β-glucan (laminarin) and counterstained with DAPI.The soluble Dectin-1 probe (red) binds to abundant luminal fungi, andthis interaction is completely blocked by soluble glucan, indicatingthat the probe is specific.

FIG. 7 depicts, in accordance with an embodiment herein, fluconazoletreatment of mice depletes intestinal fungi. Mice were treated or notwith fluconazole for 2 weeks, and colon sections were stained with asoluble Dectin-1 probe (sDEC-1) and counterstained with DAPI. Thesoluble Dectin-1 probe (red) binds to abundant luminal fungi inuntreated animals, but fluconazole treatment substantially reduces thepresence of fungi.

FIG. 8 depicts, in accordance with an embodiment herein, fungi andbacteria coexist in the gut. Colon sections were stained with ananti-fungal antibody (green, upper panels) or sDectin-1 (sDEC-1, red,lower panels) and counterstained with DAPI. Images were collected withlong exposures to reveal DAPI binding to plentiful intestinal bacteria.Fungi are abundant and in close proximity with commensal bacteria.

FIG. 9 depicts, in accordance with an embodiment herein, dectin-1 and ananti-fungal antibody specifically identify a substantial fungalpopulation in feces. Fecal pellets were homogenized and labeled withsoluble Dectin-1 (sDEC-1) and an anti-fungal antibody (α-fungi) andbriefly stained with DAPI. The samples were analyzed by flow cytometry,gating on the DAPI-intermediate and -low fractions (lower plots, sample1 & 2 are from two separate representative mice). To assess specificityof staining by flow cytometry, control feces were stained with sDEC-1 inthe presence of soluble glucan and an isotype control antibody (upperleft panel). Also feces from a mouse treated with fluconazole werestained (upper right panel). The data show that both probes identify thesame population of fungi in feces.

FIG. 10 depicts, in accordance with an embodiment herein, enhancedfrequency of IL-17 and IFN-γ producing CD4+ T cells in the intestines ofClec7a−/− mice after DSS. WT and Clec7a−/− mice were treated with 2.5%DSS for 7 days and kept on water for 4 additional days. LI-LP cells wereisolated and stimulated in vitro with PMA, ionomycin and Brefeldin A.Cells were permabilized and stained with anti-CD4, anti-IL-17 andanti-IFN-γ antibodies. Samples were analyzed using FACS. Graphsrepresent the frequency of IL-17+ and IFN-γ, cells inside the CD44 Tcell population. Each symbol represents a different mouse. ** P<0.01.Data are from one experiment representative of three.

FIG. 11 depicts, in accordance with an embodiment herein, dectin-1regulates severity of colitis. (A) Body weight in co-housed wild type(WT) and Clec7a−/− mice treated with 2.5% DSS for 7 days and kept onwater for 4 additional days. Histology score (B) on haematoxylin andeosin stained colon sections (C) was determined on day 11. (D) LI-LP andMLN cells were cultured with antibodies against CD3 and CD28. Theproduction of IL-17 and IFN-γ was measured by ELISA. (E) The expressionof tnfa (TNF-α), Il23a (IL-23p 19) and Il17a (IL-17A) in colons of WTand Clec7a−/− mice 4 days after DSS treatment was measured by qPCR andnormalized to Rp132 mRNA. Each symbol represents a different mouse. Oneof four independent experiments is shown. Error bars, s.d., * P<0.05, **P<0.01.

FIG. 12 depicts, in accordance with an embodiment herein, bacterialphyla analysis of feces from WT and Clec7a−/− mice. DNA was isolatedfrom feces of WT and Clec7a−/− littermates (n=5) and subjected toIllumina GA sequencing. (A) Rarefaction curve of phylogenic diversity infecal samples from WT and Clec7a−/− mice. The curve depicts the numberof operational taxonomic units (OTU) observed at different samplingdepths where the X axis is the number of reads in the V2/V3 region andthe Y axis is the number of OTUs observed. (B) Quantitative analysis ofthe major bacterial phyla in wild type and Clec7a−/− mice. Illumina GAdata were analyzed and presented as relative percentage of dominantbacterial phyla.

FIG. 13 depicts, in accordance with an embodiment herein, fecaltransplant does not rescue Clec7a−/− mice. WT and Clec7a−/− mice weregiven an antibiotic cocktail for 3 weeks, transplanted as indicated(red) with fecal microflora from WT or Clec7a−/− mice and treated with2.5% DSS for 7 days. (A) To access microflora depletion, feces werecollected and plated before and after antibiotic treatment (n=10). (B)Colitis progression and severity were assessed by measuring body weightduring treatment, and (C) TNF-α production in the colon on day 11. Eachsymbol represents a different mouse. One of two independent experimentsis shown. Error bars, s.d., * P<0.05, ** P<0.01.

FIG. 14 depicts, in accordance with an embodiment herein, fecalmicroflora from Clec7a−/− mice does not transfer susceptibility tocolitis in WT mice. WT mice were given an antibiotic cocktail for 3weeks, transplanted as indicated (red) with fecal microflora from WT orClec7a−/− mice and treated with 2.5% DSS for 7 days. (A) Body weight wasmeasured daily. Histology score (B), and production of IL-17 and IFN-γby LI-LP, and TNF-α production in the colon (C) were determined on day11. Each symbol represents a different mouse. One of two independentexperiments is shown. Error bars, s.d., * P<0.05. * P<0.01.

FIG. 15 depicts, in accordance with an embodiment herein, rarefactioncurve demonstrating fungal sequence coverage in WT and Clec7a−/− micebefore and after colitis. DNA was isolated from feces of WT andClec7a−/− mice before and after the onset of colitis (n=16) andsubjected to Illumina GA sequencing. The curve depicts the number ofoperational taxonomic units (OTU) observed at different sampling depthwhere the X axis is the number of ITS1-2 reads and the Y axis is thenumber of OTUs observed.

FIG. 16 depicts, in accordance with an embodiment herein, Clec7a−/− showchanges in the distribution of major fungal genera during colitis.Quantitative analysis of the three major intestinal fungal genera inwild type and Clec7a−/− mice before and after treatment with DSS wasperformed. Illumina GA data were analyzed and presented as relativepercentage of dominant fungal genera (n=16 mice). Error bars, s.d., *P<0.05, ** P<0.01.

FIG. 17 depicts, in accordance with an embodiment herein, fungipenetrate the colon of Clec7a−/− mice during colitis. Colon sectionsfrom WT and Clec7a−/− mice before and after colitis were stained withthe sDEC-1 probe and counterstained with DAPI.

FIG. 18 depicts, in accordance with an embodiment herein, fungalinvasion of colonic tissue in Clec7a−/− mice during colitis. Colonsections from WT and Clec7a−/− mice before and after colitis werestained with the antifungal antibody and counterstained with DAPI.

FIG. 19 depicts, in accordance with an embodiment herein, C. tropicalisbut not S. fibuligera exacerbates colitis in Clec7a−/− mice. WT andClec7a−/− mice were supplemented with four doses of C. tropicalis or S.fibuligera, treated with 2.5% DSS for 7 days and kept on water for 4additional days (A). Graph represent body weight in WT and Clec7a−/−mice supplemented or not with C. tropicalis (B) or S. fibuligera (C)(n=4). (D) The production of IL-17 and IFN-γ by LI-LP cells weredetermined by ELISA 4 days after DSS treatment (n=3). Data represent oneof 2 independent experiments. Error bars, s.d., * P<0.05.

FIG. 20 depicts, in accordance with an embodiment herein, S. fibuligerais dimorphic and is recognized by Dectin-1. (A) S. fibuligera was grownon Sabouraud Dextrose Agar (SDA) to obtain filamentous form (left andmiddle picture) or in Sabouraud Dextrose Broth (SDB) to obtain yeastform (far right picture). (B, C) Bone marrow-derived macrophages fromwild type or Clec7a−/− mice were IFN-γ-primed and stimulated with S.fibuligera (1:1). (B) Production of reactive oxygen species (ROS) wasmeasured with luminol-enhanced chemiluminescence (ECL). (C) TNF-αproduction was measured by ELISA after 24 h of stimulation. Data pointsare means of triplicate culture. RLU, relative light units; Error bars,s.d.

FIG. 21 depicts C. tropicalis but not S. fibuligera enhancesinflammatory cytokine production in colons of DSS-treated Clec7a−/−mice. The expression of tnfa, Il23a, Il17a, cxcl2 and defa3-defa6 incolons was measured by qPCR and normalized to Rp132 mRNA (n=3) Datarepresent one of 2 independent experiments. Error bars, s.d., * P<0.05,** P<0.01.

FIG. 22 depicts, in accordance with an embodiment herein, reducedclearance of supplemented C. tropicalis in Clec7a−/− mice during colitis(A) WT and Clec7a−/− mice were supplemented with four doses (1×10₈yeast/mouse/dose) of Candida tropicalis (C. trop) or Saccharomycopsisfibuligera (S. fib) according to the schedule shown, and colitis wasinduced with 2.5% DSS in the drinking water for 7 days followed by 4days of recovery. Feces were collected before supplementation withrespective fungi (NT), or before (C. trop or S. fib) and after (DSS/C.trop or DSS/S. fib) DSS treatment. Feces were analyzed by qPCR for thepresence of (B) C. tropicalis or (C) S. fibuligera rDNA before (B and C,left) and after (B and C, right) DSS treatment. The left panel of (B)was used in FIG. 3G and is included again here for comparison. Eachsymbol represents a different mouse. * P<0.05, ns (not significant).Data represent one of 2 independent experiments.

FIG. 23 depicts, in accordance with an embodiment herein, anti-fungaltherapy ameliorates colitis in Clec7a−/− mice. WT and Clec7a−/− micewere given fluconazole in the drinking water for total of 14 daysstarting 2 days prior the induction of DSS colitis. (A) Cells wereisolated and stimulated in vitro with PMA, ionomycin and Brefeldin A.Cells were permeabilized and stained with anti-CD4, anti-IL-17 andanti-IFN-γ antibodies. Samples were analyzed by flow cytometry. Graphsrepresent the frequency of IL-17+ and IFN-γ+ cells inside the CD4+ Tcell population. (B) IL-17 and IFN-γ produced by LI-LP, and (C) TNF-αproduction in the colon was determined by ELISA. (D) The expression oftnfa, Il23a and Il17a in colons was measured by qPCR and normalized toRpl32 mRNA (n=3). Data were obtained from three independent experimentswith similar results. Each symbol represents a different mouse. One ofthree independent experiments is shown. Error bars, s.d., * P<0.05, **P<0.01.

FIG. 24 depicts, in accordance with an embodiment herein, analysis ofCLEC7A SNPs and haplotypes. (A) Location of CLEC7A SNPs. Cartoon ofCLEC74 gene with a track showing position on Human Genome Build 37, atrack showing the location of the 5 SNPs (in red) examined in thisstudy, and a track showing exon/intron structure of transcript variants.(B) Linkage disequilibrium between CLEC7A SNPs. Using Haploview v4,linkage disequilibrium between CLEC7A SNPs was plotted; red diamondswithout numbers indicate r₂=1. The rs2078178-rs16910631 haplotype ismarked as “Block 1”.

FIG. 25 depicts, in accordance with an embodiment herein, a table ofCLEC7A risk haplotype analysis of MRUC and Non-MRUC patients.

FIG. 26 depicts, in accordance with an embodiment herein, a table ofCLEC7A risk haplotype analysis of MRUC and Non-MRUC patients compared tohealthy controls.

DESCRIPTION OF THE INVENTION

All references cited herein are incorporated by reference in theirentirety as though fully set forth. Unless defined otherwise, technicaland scientific terms used herein have the same meaning as commonlyunderstood by one of ordinary skill in the art to which this inventionbelongs. Singleton et al., Dictionary of Microbiology and MolecularBiology 3rd ed., J. Wiley & Sons (New York, N.Y. 2001); March, AdvancedOrganic Chemistry Reactions, Mechanisms and Structure 5th ed., J. Wiley& Sons (New York, N.Y. 2001); and Sambrook and Russel, MolecularCloning: A Laboratory Manual 3rd ed., Cold Spring Harbor LaboratoryPress (Cold Spring Harbor, N.Y. 2001), provide one skilled in the artwith a general guide to many of the terms used in the presentapplication.

One skilled in the art will recognize many methods and materials similaror equivalent to those described herein, which could be used in thepractice of the present invention. Indeed, the present invention is inno way limited to the methods and materials described.

“IBD” as used herein is an abbreviation of inflammatory bowel disease.

“CD” as used herein is an abbreviation of Crohn's Disease.

“SNP” as used herein is an abbreviation of single nucleotidepolymorphism.

As used herein, the term “biological sample” means any biologicalmaterial from which nucleic acid molecules can be prepared. Asnon-limiting examples, the term material encompasses whole blood,plasma, saliva, cheek swab, or other bodily fluid or tissue thatcontains nucleic acid.

As disclosed herein, the intestinal microflora typically equated withbacteria, influences diseases such as obesity and inflammatory boweldisease (IBD). Here, the inventors demonstrate that the mammalian gutcontains a rich fungal community that interacts with the immune systemthrough the innate immune receptor Dectin-1. Mice lacking Dectin-1 aresusceptible to chemically-induced colitis and show elevated Th1 and Th17mucosal immune responses. Disease susceptibility was due to alteredresponses to indigenous fungi. In humans, the inventors identified apolymorphism in the gene for Dectin-1 (CLEC7A) that is strongly linkedto a severe form of ulcerative colitis. Together the inventors' findingsreveal a novel eukaryotic fungal community in the gut that coexists withbacteria and significantly expands the repertoire of organismsinteracting with the intestinal immune system to influence health anddisease.

In one embodiment, the present invention provides a method of diagnosingsusceptibility to inflammatory bowel disease in an individual,comprising obtaining a sample from the individual, assaying the sampleto determine the presence or absence of one or more risk variants at theDectin-1 gene (CLEC7A), and diagnosing susceptibility to inflammatorybowel disease in the individual based on the presence of one or morerisk variants at the Dectin-1 gene (CLEC7A). In another embodiment, theinflammatory bowel disease is a severe form of ulcerative colitis. Inanother embodiment, the present invention provides a method ofdiagnosing susceptibility to a severe form of ulcerative colitis basedon the inability to control fungi in the gut of the individual.

In another embodiment, the present invention provides a method ofdiagnosing colitis and/or a disease mediated by an elevated Th1 and/orTh17 mucosal immune response in an individual, comprising obtaining asample from the individual, assaying the sample to determine thepresence or absence of functioning Dectin-1 relative to a normalsubject, and diagnosing colitis and/or a disease mediated by an elevatedTh1 and/or Th17 mucosal immune response based on the absence offunctioning Dectin-1 relative to a normal subject. In anotherembodiment, an absence of functioning Dectin-1 is characterized by adeficiency of Dectin-1 in the individual.

In another embodiment, the present invention provides a method oftreating inflammatory bowel disease in an individual, comprisingobtaining a sample from the individual, assaying the sample to determinea deficiency of Dectin-1 in the individual, and treating the individual.

Beneficial commensal bacteria called “probiotic bacteria” have beenutilized for treatment of diseases and have been developed into aprofitable industry bringing large revenue. As disclosed herein, fungalmicrobiome (mycobiome) interacts with the host mucosal immune system andwith the bacterial gut microbiome to influence disease. The inventorsfound that certain species of commensal fungi are able to induceprotective mechanisms that ameliorate intestinal inflammation andcolitis. Mice supplemented with Saccharomycopsis fibuligera, a commensalfungus isolated from murine gut, showed decreased gut inflammation andmilder intestinal disease in an experimental model of colitis). It worthnoting that Saccharomycopsis fibuligera has been used in rice wineproduction for centuries, but its probiotic properties have not beeninvestigated. Other commensal fungi isolated from mouse or human gutwould display similar probiotic properties. In one embodiment, probioticfungi can be used as a tool for prophylactic and treatment of intestinaldisorders, obesity, metabolic syndrome and colon cancer.

Furthermore, in another embodiment, mycobiome may be used as adiagnostic marker. Changes in the composition of the gut bacterialmicrobiome described as “dysbiosis” have been associated with intestinalinflammation and metabolic syndrome. Increased representation of gutbacteria belonging to Prevotellaceae and TM7 phyla can be linked todiseases such as IBD, obesity and metabolic syndrome. Specific changesto bacterial microbiome can be used as a marker of a disease and thatthe bacterial microbiome can be actually used as a diagnostic tool innumber of diseases such as IBD, obesity and metabolic syndrome. Asdisclosed herein, microbiome is a dynamic structure which changes duringinflammation and according to the disease state. The inventors foundthat certain fungal genera (Candida, Trichosporon) known asopportunistic pathogens expand according to disease severity whereas therelative abundance of probiotic fungal genera (such as Saccharomyces andSaccharomycopsis) decreases (see the attached manuscript). In oneembodiment, the present invention provides for methods of diagnosing adisease, where changes in the gut mycobiome can be used as a diagnosticmarker for a disease state and severity. In another embodiment, thedisease is IBD, obesity, metabolic syndrome and/or cancer.

In another embodiment, the present invention provides a method oftreatment, where gut mycobiome may be altered using targeted antifungaltherapy as a tool for treatment. Studies of the bacterial microbiomehave additionally shown that targeted antibiotic therapy can bebeneficial in treatment of IBD, obesity, metabolic syndrome, coloncancer and neurological disorders. The inventors showed that certainspecies of gut commensal fungi can be protective whereas other fungalspecies can be pathogenic during certain conditions and can lead toexacerbated disease. As disclosed herein, the inventors demonstratedthat certain commensal fungi known as opportunistic pathogens (Candidaand Trichosporon species) can contribute to development of intestinalinflammation in which case antifungal therapy targeting these specificspecies can be used as a mean of treatment. In one embodiment, targetedanti-fungal therapy can be used for treatment of forms of IBD, obesity,metabolic syndrome and colon cancer. In another embodiment, the gutmycobiome may influence gut bacterial microbiome, a property used as atreatment protocol itself.

A variety of methods can be used to determine the presence or absence ofa variant allele or haplotype. As an example, enzymatic amplification ofnucleic acid from an individual may be used to obtain nucleic acid forsubsequent analysis. The presence or absence of a variant allele orhaplotype may also be determined directly from the individual's nucleicacid without enzymatic amplification.

Analysis of the nucleic acid from an individual, whether amplified ornot, may be performed using any of various techniques. Useful techniquesinclude, without limitation, polymerase chain reaction based analysis,sequence analysis and electrophoretic analysis. As used herein, the term“nucleic acid” means a polynucleotide such as a single ordouble-stranded DNA or RNA molecule including, for example, genomic DNA,cDNA and mRNA. The term nucleic acid encompasses nucleic acid moleculesof both natural and synthetic origin as well as molecules of linear,circular or branched configuration representing either the sense orantisense strand, or both, of a native nucleic acid molecule.

The presence or absence of a variant allele or haplotype may involveamplification of an individual's nucleic acid by the polymerase chainreaction. Use of the polymerase chain reaction for the amplification ofnucleic acids is well known in the art (see, for example, Mullis et al.(Eds.), The Polymerase Chain Reaction, Birkhauser, Boston, (1994)).

A TaqmanB allelic discrimination assay available from Applied Biosystemsmay be useful for determining the presence or absence of a variantallele. In a TaqmanB allelic discrimination assay, a specific,fluorescent, dye-labeled probe for each allele is constructed. Theprobes contain different fluorescent reporter dyes such as FAM and VICTMto differentiate the amplification of each allele. In addition, eachprobe has a quencher dye at one end which quenches fluorescence byfluorescence resonant energy transfer (FRET). During PCR, each probeanneals specifically to complementary sequences in the nucleic acid fromthe individual. The 5′ nuclease activity of Taq polymerase is used tocleave only probe that hybridize to the allele. Cleavage separates thereporter dye from the quencher dye, resulting in increased fluorescenceby the reporter dye. Thus, the fluorescence signal generated by PCRamplification indicates which alleles are present in the sample.Mismatches between a probe and allele reduce the efficiency of bothprobe hybridization and cleavage by Taq polymerase, resulting in littleto no fluorescent signal. Improved specificity in allelic discriminationassays can be achieved by conjugating a DNA minor grove binder (MGB)group to a DNA probe as described, for example, in Kutyavin et al.,“3′-minor groove binder-DNA probes increase sequence specificity at PCRextension temperature, “Nucleic Acids Research 28:655-661 (2000)). Minorgrove binders include, but are not limited to, compounds such asdihydrocyclopyrroloindole tripeptide (DPI,).

Sequence analysis also may also be useful for determining the presenceor absence of a variant allele or haplotype.

Restriction fragment length polymorphism (RFLP) analysis may also beuseful for determining the presence or absence of a particular allele(Jarcho et al. in Dracopoli et al., Current Protocols in Human Geneticspages 2.7.1-2.7.5, John Wiley & Sons, New York; Innis et al., (Ed.), PCRProtocols, San Diego: Academic Press, Inc. (1990)). As used herein,restriction fragment length polymorphism analysis is any method fordistinguishing genetic polymorphisms using a restriction enzyme, whichis an endonuclease that catalyzes the degradation of nucleic acid andrecognizes a specific base sequence, generally a palindrome or invertedrepeat. One skilled in the art understands that the use of RFLP analysisdepends upon an enzyme that can differentiate two alleles at apolymorphic site.

Allele-specific oligonucleotide hybridization may also be used to detecta disease-predisposing allele. Allele-specific oligonucleotidehybridization is based on the use of a labeled oligonucleotide probehaving a sequence perfectly complementary, for example, to the sequenceencompassing a disease-predisposing allele. Under appropriateconditions, the allele-specific probe hybridizes to a nucleic acidcontaining the disease-predisposing allele but does not hybridize to theone or more other alleles, which have one or more nucleotide mismatchesas compared to the probe. If desired, a second allele-specificoligonucleotide probe that matches an alternate allele also can be used.Similarly, the technique of allele-specific oligonucleotideamplification can be used to selectively amplify, for example, adisease-predisposing allele by using an allele-specific oligonucleotideprimer that is perfectly complementary to the nucleotide sequence of thedisease-predisposing allele but which has one or more mismatches ascompared to other alleles (Mullis et al., supra, (1994)). One skilled inthe art understands that the one or more nucleotide mismatches thatdistinguish between the disease-predisposing allele and one or moreother alleles are preferably located in the center of an allele-specificoligonucleotide primer to be used in allele-specific oligonucleotidehybridization. In contrast, an allele-specific oligonucleotide primer tobe used in PCR amplification preferably contains the one or morenucleotide mismatches that distinguish between the disease-associatedand other alleles at the 3′ end of the primer.

A heteroduplex mobility assay (HMA) is another well known assay that maybe used to detect a SNP or a haplotype. HMA is useful for detecting thepresence of a polymorphic sequence since a DNA duplex carrying amismatch has reduced mobility in a polyacrylamide gel compared to themobility of a perfectly base-paired duplex (Delwart et al., Science262:1257-1261 (1993); White et al., Genomics 12:301-306 (1992)).

The technique of single strand conformational, polymorphism (SSCP) alsomay be used to detect the presence or absence of a SNP and/or ahaplotype (see Hayashi, K., Methods Applic. 1:34-38 (1991)). Thistechnique can be used to detect mutations based on differences in thesecondary structure of single-strand DNA that produce an alteredelectrophoretic mobility upon non-denaturing gel electrophoresis.Polymorphic fragments are detected by comparison of the electrophoreticpattern of the test fragment to corresponding standard fragmentscontaining known alleles.

Denaturing gradient gel electrophoresis (DGGE) also may be used todetect a SNP and/or a haplotype. In DGGE, double-stranded DNA iselectrophoresed in a gel containing an increasing concentration ofdenaturant; double-stranded fragments made up of mismatched alleles havesegments that melt more rapidly, causing such fragments to migratedifferently as compared to perfectly complementary sequences (Sheffieldet al., “Identifying DNA Polymorphisms by Denaturing Gradient GelElectrophoresis” in Innis et al., supra, 1990).

Other molecular methods useful for determining the presence or absenceof a SNP and/or a haplotype are known in the art and useful in themethods of the invention. Other well-known approaches for determiningthe presence or absence of a SNP and/or a haplotype include automatedsequencing and RNAase mismatch techniques (Winter et al., Proc. Natl.Acad. Sci. 82:7575-7579 (1985)). Furthermore, one skilled in the artunderstands that, where the presence or absence of multiple alleles orhaplotype(s) is to be determined, individual alleles can be detected byany combination of molecular methods. See, in general, Birren et al.(Eds.) Genome Analysis: A Laboratory Manual Volume 1 (Analyzing DNA) NewYork, Cold Spring Harbor Laboratory Press (1997). In addition, oneskilled in the art understands that multiple alleles can be detected inindividual reactions or in a single reaction (a “multiplex” assay). Inview of the above, one skilled in the art realizes that the methods ofthe present invention for diagnosing or predicting susceptibility to orprotection against CD in an individual may be practiced using one or anycombination of the well known assays described above or anotherart-recognized genetic assay.

One skilled in the art will recognize many methods and materials similaror equivalent to those described herein, which could be used in thepractice of the present invention. Indeed, the present invention is inno way limited to the methods and materials described. For purposes ofthe present invention, the following terms are defined below.

EXAMPLES

The following examples are provided to better illustrate the claimedinvention and are not to be interpreted as limiting the scope of theinvention. To the extent that specific materials are mentioned, it ismerely for purposes of illustration and is not intended to limit theinvention.

One skilled in the art may develop equivalent means or reactants withoutthe exercise of inventive capacity and without departing from the scopeof the invention.

Example 1 Generally

The intestinal microflora, typically equated with bacteria, influencesdiseases such as obesity and inflammatory bowel disease (IBD). Here theinventors show that the mammalian gut contains a rich fungal communitythat interacts with the immune system through the innate immune receptorDectin-1. Mice lacking Dectin-1 are susceptible to chemically-inducedcolitis and show elevated Th11 and Th17 mucosal immune responses.Disease susceptibility was due to altered responses to indigenous fungi.In humans we identified a polymorphism in the gene for Dectin-1 (CLEC7A)that is strongly linked to a severe form of ulcerative colitis. Togetherour findings reveal a novel eukaryotic fungal community in the gut thatcoexists with bacteria and significantly expands the repertoire oforganisms interacting with the intestinal immune system to influencehealth and disease.

Mucosal fungal infections are relatively common in Crohn's Diseasepatients, and antibodies against fungal antigens (ASCA) are a wellaccepted clinical marker for disease severity. However what fungipopulate the intestine and how immunity to them might play a role ininflammatory disease is currently unknown. Fungi are sensed by number ofinnate immune receptors among which Dectin-1, expressed on myeloidcells, is critical for host defense. The inventors found that commensalfungi populate the murine gut and that Dectin-1^(−/−) mice are moresusceptible to experimental colitis characterized by increasedinfiltration of Th17 and Th1 cells in the colon. Interestingly thispathology was driven by intestinal fungi, and antifungal therapyameliorated colitis severity in Dectin-1^(−/−) mice. Deep sequencinganalysis of the fungal microbiome in murine feces revealed fungalspecies that are overrepresented in the gut during colitis. Micesupplemented with a specific commensal fungus experienced more severecolitis and augmented Th17 mucosal responses in absence of Dectin-1,while another commensal fungus enhanced Th17 responses in Dectin-1^(−/−)mice but did not further affect the intestinal pathology. The datademonstrate that altered interactions between the fungal microflora andthe host mucosal immune system can profoundly influence intestinalpathology.

Example 2 Commensal Fungi and Dectin-1 Interactions

The inventors examined the distribution of fungi in the murinegastrointestinal tract and detected fungal rDNA throughout theintestines with highest densities in the terminal colon of C57BL/6 (FIG.1A) and 129S2/Sv (FIG. 5) mice. They stained colonic tissue sections andobserved that fungi are abundant and in close proximity with commensalbacteria (FIGS. 1B and C and FIG. 6 to 8). Furthermore, the inventorsfound that a soluble Dectin-1 probe binds to 5 to 7% of the fecalmaterial consisting of fungal cells with various morphologies (FIG. 1D).Fungi were also present in rat, guinea pig, rabbit, pig, dog, and humanfeces (FIG. 1E). Together the data demonstrate that commensal fungicontribute to the intestinal microbial community in many species.

The inventors also examined whether gut fungi can be detected by theimmune system upon intestinal insult when barrier integrity iscompromised. They utilized a mouse model of dextran sodium sulfate(DSS)-induced colitis extended to allow antibody responses to develop.They found that DSS-induced intestinal inflammation led to thedevelopment of circulating IgM and IgG antibodies to fungi (ASCA) (FIG.1F), suggesting that fungal antigens indigenous to the gut might beresponsible for the induction of ASCA during colitis. Since they foundthat gut commensal fungi are recognized by Dectin-1, we tested whetherDectin-1-deficient mice (Clec7a−/−) are susceptible to DSS-inducedcolitis. Clec7a−/− mice experienced increased weight loss (FIG. 2A) anddisplayed altered histology characterized by increased mucosal erosion,crypt destruction, inflammatory cell infiltration, and TNF-α productionin the colon (FIG. 2B to D) as compared to their wild type (WT)littermate controls. They detected augmented production of IFN-γ andIL-17 in mesenteric lymph nodes (MLNs) and colons from Clec7a−/− mice(FIGS. 2E and F) which correlated with higher frequencies ofinflammatory Th and Th17 cells (FIG. 2E and FIG. 10). Identical resultswere obtained comparing co-housed Clec7a−/− and WT mice. These resultsindicate that Dectin-1 deficiency leads to increased susceptibility tocolitis. Since many studies have documented the importance of bacteriain intestinal inflammation, we examined whether differences in bacteriacould contribute to the susceptible phenotype of Dectin-1-deficientmice. They observed no significant differences in major phyla ofcommensal bacteria between WT and Clec7a−/− mice. To directly determinewhether microflora can transfer disease, the inventors depletedintestinal bacteria and fungi with antibiotics transplanted with fecalmicroflora from WT or Clec7a−/− mice, and exposed mice to DSS. Fecalmicroflora from Clec7a−/− mice did not transfer susceptibility todisease (FIGS. 2G and H).

There is very little known about what commensal fungi populate themurine gut or how they might contribute to colitis in Dectin-1 deficientmice. To define the mouse intestinal fungal microbiome DNA was isolatedfrom murine intestinal luminal content, and the internal transcribedspacer region (ITS1-2) of fungal rDNA was amplified and subjected tohighthroughput sequencing. Combining data from 23 mice analyzed, weobtained over 30 Mb of raw data from 454 pyrosequencing and over 2.2 GBof raw data from Illumina GA sequencing together containing over 1.3million individual sequences which passed quality control. Detailedanalysis identified over 100 different well-annotated fungal speciesrepresenting at least 50 genera illustrating the fungal diversity. Inaddition, over 100 novel/unannotated fungi were identified representingthe large uncharacterized nature of the fungal biome in the gut.Interestingly, 97.3% of all the fungal sequences identified, belonged to10 fungal species with 65.2% of the sequences belonging to a singlefungus: Candida tropicalis (FIG. 3A). The inventors also examined mousefood, and found that 7 of the 20 most commonly represented fungi foundin the gut were present in the mouse food, but these species ultimatelyaccounted for only 1.5% of the fungi in the intestines (FIG. 17, 18),suggesting that highly represented fungal species are indigenous to thegut and are not delivered with the food.

Studies have shown that intestinal inflammation can lead to changes incommensal bacterial communities that affect the host. One study hasreported increased fungal burden in intestines of Crohn's Diseasepatients, and another has shown increased colonization with exogenouslyadded C. albicans during DSS colitis in mice. However, whether colitisdirectly affects the makeup of the commensal fungal microbiome is notknown. Notably, the inventors found that during colitis in Clec7a−/−mice the proportion of opportunistic pathogenic fungi including Candidaand Trichosporon increases while the non-pathogenic Saccharomyces isdecreased (FIG. 3B). Examination of colons revealed that fungi invadeinflamed tissues in DSS-treated Clec7a−/− mice but remain in the lumenof DSS-treated WT mice (FIG. 3C and FIG. 17, 18). These data areconsistent with the observation that intestinally conditionedDectin-1-deficient dendritic cells are less capable of killing C.tropicalis in vitro (FIG. 3D). Together the data suggest thatDectin-1-deficiency leads to altered immunity to commensal fungi in thegut.

Given that C. tropicalis is an opportunistic pathogen, we furtheranalyzed its role during colitis. The inventors supplemented mice withC. tropicalis and subjected them to DSS. For comparison, another groupof mice was supplemented with S. fibuligera, a nonpathogenic fungusthat, like C. tropicalis, grows in yeast and filamentous forms, and thatthe inventors have identified as a common commensal organism recognizedby Dectin-1. They found that colitis symptoms such as weight loss, cryptloss and inflammatory cell infiltration were more severe in Clec7a−/−mice supplemented with C. tropicalis compared to the Clec7a−/− controls(FIG. 3E and FIG. 22B). In contrast, C. tropicalis supplementation didnot aggravate DSS colitis in WT mice. Consistent with the pathology,they inventors detected increased IL-17 and IFN-γ production by T cellsfrom the MLNs and colons of Clec7a−/− mice supplemented with C.tropicalis compared to Clec7a−/− controls (FIG. 3F and FIG. 22D). Theyfurther observed increased message for TNF-α, IL-23p 19, IL-17a, Cxcl2and defensins in colons of Clec7a−/− mice supplemented with C.tropicalis compared to Clec7a−/− controls (FIG. 24). The observedincrease in cytokine production and aggravated intestinal inflammationcorrelated with higher loads of C. tropicalis in the intestines ofDSS-treated Clec7a−/− mice (FIG. 3G and FIG. 22B). In contrast, S.fibuligera supplementation did not contribute to colitis pathology(FIGS. 3E, F and FIGS. 19C, D and 24) and fungal loads were equivalentin the intestines of WT and Clec7a−/− mice (FIG. 25). Therefore the datasuggest that an inability of Clec7a−/− mice to mount effective immuneresponses to specific intestinal fungi creates conditions that promoteinflammation.

To determine whether the altered fungal burden during colitis directlycontributes to disease severity in the absence of Dectin-1, theinventors suppressed fungal growth with fluconazole, a specificanti-fungal drug (FIG. 7). The inventors found that fluconazoletreatment during colitis led to reduced weight loss (FIG. 4A), andmilder histological disease characteristics (FIG. 4B) specifically inClec7a−/− mice. They similarly observed decreased Th1 and Th17 responses(FIG. 4C, D and FIG. 26A, B), and decreased production of inflammatorycytokines (FIG. 23C, D). Taken together, these results further supportthe conclusion that an inability to control fungi in the gut leads tomore severe colitis in Dectin-1 knockout mice.

Having established a role for Dectin-1 in fungal control during colitisin mice, we next explored whether there is an association betweeninflammatory bowel disease and genetic variation of the human Dectin-1gene (CLEC7A). Since the mouse model suggested that Dectin-1 is involvedin contributing to the severity of colonic disease, it was a logicalstep to focus human studies on ulcerative colitis (UC), a disease of thecolon, and in particular on severe UC. Up to 30% of patients with UCrequire colectomy usually for severe disease that will not respond tomedical therapy including systemic corticosteroids, cyclosporine andbiological therapies (medically refractory UC (MRUC)). The inventorscompared CLEC7A alleles in an MRUC group to a group of patients with UCwho had not required colectomy (non-MRUC) (29). They identified anassociation of CLEC7A SNP rs2078178 in patients with MRUC (logisticregression p=0.007). Notably, a two marker haplotype,rs2078178-rs16910631, was more strongly associated with MRUC (AGhaplotype; p logistic regression=0.00013/p fisher=0.0005; FIG. 4E andFIG. 24A, B), shorter time to surgery and thus with a more severe UC(FIG. 4F). Compared to healthy controls, the haplotype is stronglyassociated with MRUC and not with non-MRUC, further consistent with theidea that the haplotype is associated with severe disease. CLEC7A hasnot been identified in any GWAS study yet as an IBD susceptibility gene.Unlike susceptibility genes which predispose to disease, severity genevariants aggravate disease that is initially established through othermechanisms. The CLEC7A risk haplotype here fits this latter situationand agrees with the observation that Clec7a−/− mice do not developspontaneous colitis.

In summary, the gut is populated with a diverse community of fungi thathas been poorly appreciated. The inventors characterize the murine gutmycobiome and show that anti-fungal host defense mediated by Dectin-1can be an important factor in determining the severity of colitis. Theyobserved that, similar to bacteria, some fungi are detrimental andothers are not. Since they found that bacteria and fungi occupy similarniches in the gut, it will be interesting to determine to what extentthe populations interact and how this may influence health and disease.They have demonstrated that Dectin-1 controls mucosal immunity to fungiin the gut and that Dectin-1-deficiency leads to exaggerated Th1 andTh17 responses and more severe disease in a mouse model of colitis. Thedata shows that Dectin-1 is necessary to control invasion of mucosaltissues by commensal fungi during colitis, however the receptor may alsobe involved in suppression of intestinal inflammation through additionalmechanisms. In humans, a specific variant of the gene for Dectin-1 isstrongly associated with a severe form of ulcerative colitis requiringcolectomy. This can provide better therapies for IBD, and can beespecially beneficial to patients with particularly severe forms ofulcerative colitis carrying the risk haplotype of the gene for Dectin-1.Overall, the idea that fungi are present in the gut and that theyinteract strongly with the immune system will fundamentally alter howgut microflora and inflammatory bowel diseases are viewed.

Example 3 Mice and Fungal Strains

6-10 weeks old female C57BL/6J mice were purchased from JacksonLaboratories (Bar Harbor, Me.). Clec7a−/− generated as previouslydescribed were crossed 9 generations onto the C57BL/6J background.Progeny homozygous for Clec7a−/− and wild-type littermates aged 7-12weeks were used where indicated. All animals were housed under specificpathogen-free conditions at the Cedars-Sinai Medical Center andexperiments were performed after prior approval by the InstitutionalAnimal Care and Use Committee at Cedars-Sinai Medical Center andconformed to the policies and procedures of the Comparative MedicineDepartment. Candida tropicalis (ATCC 750) and Saccharomyces cerevisiae(ATCC 201388) were obtained directly from the American Type CultureCollection (Manassas, Va.). Saccharomycopsis fibuligera was isolateddirectly from murine feces and identified by rDNA sequencing. Yeastswere cultured in aerobic conditions on Sabouraud Dextrose Broth (SDB;EMD Chemicals) at 37° C.

Example 4 In Situ Staining of Intestinal Fungi

OCT-embedded intestinal specimens were sectioned, mounted on microscopeslides and then incubated for 40 min in PBS containing 2% FCS. Murinesoluble Dectin-1 (sDec-1) was generated and biotin-labeled as previouslydescribed. sDec-1 (10 μg/ml) was fluorescently labeled withstreptavidin-Alexa 647 (2 μg/ml, Invitrogen) (sDec-1-Alexa647), andintestinal sections were stained for 1 hr. To block Dectin-1interaction, sDec-1-Alexa647 was incubated with 1 μg/ml laminarin(soluble 1-glucan from Laminaria digitata, Sigma) and intestinalsections were stained as previously described. Alternatively, intestinalsections were stained with FITC conjugated rabbit anti-Candidapolyclonal antibody (Meridian Life Science, Cincinnati, Ohio). Theinventors found that this “anti-Candida antibody” was cross-reactivewith a wide variety of fungal species including C. tropicalis, Calbicans, S. cerevisiae, S. fibuligera and A. fumigatus, but did notstain bacteria (E. coli, C. jejuni, S. aureus). Therefore throughoutthis study we have referred to the antibody as an “anti-fungalantibody”. Slides were rinsed with PBS and stained for 5 min with 0.1μg/ml 4′,6-diamidino-2-phenylindole (DAPI, Invitrogen) and overlaid withmounting medium (Vectashield; Vector, Burlingame, Calif.). Slides wereexamined using a Zeiss Axio Observer Fluorescence microscope. Allcompared images were collected and processed identically. Colons fromFluconazole (0.5 mg/ml for 2 weeks in the drinking water) treated micewere used in control staining.

Example 5 Staining of Fungi in the Feces

Fecal pellets were collected, homogenized in PBS containing 2% FCS andfiltered through a mesh to obtain homogeneous fecal suspensions. Fecalsuspensions were stained for 1 hour with sDec-1-Alexa647, anti-fungalFITC-conjugated antibody and DAPI as previously described. Controlsuspensions were stained with laminarin blocked sDec-1-Alexa647,FITC-labeled rabbit-IgG-isotype control antibody and DAPI. Data wereanalyzed by flow cytometry. To visualize intestinal fungi bound toDectin-1, fecal samples were stained with sDec-1-Alexa647, fixed in 4%formaldehyde and sorted using a FACSAria (BD Biosciences). Sorted fungalcells were viewed using a TCS SP5 laser-scanning confocal microscope(Leica). Detection of anti-Saccharomyces cerevisiae antibodies (ASCA)For the induction of ASCA antibody responses to intestinal fungalantigens, mice were kept on 2.5% DSS supplemented water for 2 cycles of7 days each. After each cycle mice were given regular water for 2 weeks.Then mice were sacrificed, blood was collected and blood serum wasobtained. ELISA detection of ASCA specific IgM and IgG was carried outas previously described. Samples were read at 405 nm on a MolecularDevices E-Max microtiter plate reader (Menlo Park, Calif.).

Example 6 Candida Killing Assay

Intestinally conditioned dendritic cells (DCs) were prepared from WT andClec7a−/− mice as previously described (4). Candida tropicalis (1×10₅)was resuspended in RPMI 1640 supplemented with 5% fetal bovine serum(FBS) and added onto 1×10₅ DCs, and incubated at 37° C. in a 5% CO₂incubator for 1 hour. Wells were washed and fresh media containingfluconazole (300 μg/ml) was added. At 6 hours and 18 hours, DCs werewashed three times with PBS, lysed in water, and C. tropicalis CFU werecalculated by plating on SDB agar.

Example 7 Induction of DSS Colitis and Histopathology

WT and Clec7a−/− mice were cohoused for three weeks prior theexperiments. Alternatively, WT and Clec7a−/− littermates were used whereindicated. For the induction of colitis, mice were given drinking watersupplemented with 2.5% (w/v) Dextran sulphate sodium (DSS, MPBiomedicals, LLC, Aurora, Ohio) for 7 days and sacrificed at day 12. Forablation of intestinal fungi, mice were given Fluconazole (0.5 mg/ml,Sigma) in the drinking water for total of 14 days starting 2 days priorthe induction of DSS colitis. In some experiments, prior and uponcolitis induction, mice were supplemented every other day with fourdoses (1×10₈ yeast/mouse/dose) of Candida tropicalis or Saccharomycopsisfibuligera as shown in FIG. 19. Body weight, gross blood, and stoolconsistency were analyzed on a daily basis. Paraffin embedded colontissues were sectioned and stained with H&E for pathology assessment.Assessment of the severity of colitis was measured by the diseaseactivity index (DAI) as previously described.

Example 8 Antibiotic Treatment and Microbiota Reconstitution

For depletion of intestinal microbiota, mice were given an antibioticcocktail, containing ampicillin (1 g/l; Sigma, St. Louis, Mo.),vancomycin (500 mg/l, Sigma), neomycin sulfate (1 g/l, Sigma),metronidazole (1 g/l, Sigma) and fluconazole (0.5 mg/ml, Sigma) indrinking water for 3 weeks. Fecal pellets were collected and tested formicrobiota depletion by culture method (aerobic and anaerobic),sDec-1-Alexa647 staining (to evaluate depletion of fungi) andquantitative PCR. Microbiota-depleted mice were both, orally gavaged andintrarectally administrated with homogenates prepared from WT orClec7a−/− feces, and 10 days after reconstitution DSS administration wasstarted.

Example 9 Isolation of Intestinal Mucosa, Colonic Cells and LargeIntestine Lamina Propria (LI-LP) Lymphocytes

LI-LP lymphocytes were isolated as previously described with somemodifications. Briefly, colons were isolated, opened longitudinally,washed of fecal contents and then cut into 1 cm pieces. Intestinalpieces were transferred into HBSS medium (Sigma), supplemented with 5%fetal bovine serum (FBS) and 2 mM EDTA, and were shaken for 15 min at37° C. The suspensions were filtered through a mesh and the filtratecontaining the mucosa and mucosa associated microflora was used furtherfor DNA isolation. The remaining tissue was washed, cut in small piecesand subsequently incubated in digestion medium consisting of RPMI 1640,5% FBS, 0.5 mg/ml collagenase type VIII (Sigma), 5 U/ml DNase (RocheDiagnostics), 100 IU/ml penicillin and 100 μg/ml streptomycin for 30 minat 37° C. by gentle shaking. The cell suspensions were filtered througha mesh, and then centrifuged at 1300 rpm. Cell suspensions were culturedovernight and TNF-α production by colonic cells was measured by ELISA(BioLegend, San Diego, Calif.).

The rest of the pellets were resuspended in 6 ml of 40% Percoll (GEHealthcare Bio-Sciences AB, Uppsala, Sweden), overlaid on 3 ml of 70%Percoll and centrifuged at 2000 rpm for 20 min at 25° C. The interfacecells were collected and used as LI-LP lymphocytes.

Example 10 Lymphocyte Stimulation and Cytokine Analysis

Cell suspensions were prepared from MLNs and the LI-LP as describedabove. Cells were incubated with 50 ng/ml phorbol 12-myristate13-acetate (PMA; Sigma-Aldrich), 500 ng/ml ionomycin (Sigma-Aldrich) and10 μg/ml Brefeldin A (BFA; Sigma-Aldrich) in complete RPMI media at 37°C. for 6 h. After surface staining with CD4, cells were permeabilizedand intracellular cytokine staining was performed using APC-labeledanti-IFN-γ mAb (XMG1.2; BD Biosciences) and PE-labeled anti-IL-17 mAb(TC11-18H10; BD Biosciences) according to the manufacturer'sinstructions. Flow cytometry was performed using a LSRII (BDBiosciences) and data were analyzed with FlowJo software (TreeStarInc.).

For detection of cytokines by ELISA, MLN cells and LI-LP lymphocyteswere stimulated with 10 μg/ml plate bound anti-CD3 and anti-CD28antibodies (BioLegend, San Diego, Calif.). Supernatants were collectedafter 36 hrs and analyzed for IFN-γ and IL-17 production by ELISA(BioLegend, San Diego, Calif.).

Example 11 DNA Isolation, Fungal and Bacterial rDNA Gene QuantitativeAnalysis

Intestinal mucosa from ileum, caecum, proximal and distal colon wasobtained as described above. Feces were collected from non-treated orDSS treated C57BL/6J and Clec7a−/− mice. Additionally, feces werecollected from BALB/c mice, 129S2/Sv mice, Rat, Guinea Pig, Pig, Rabbitand Dog, all breed and housed in the animal facility of Cedars-Sinaimedical center. Human fecal samples from 3 healthy donors were collectedafter obtaining informed consent and immediately frozen. Fecal ormucosal samples were resuspended in 50 mM Tris buffer (pH7.5) containing1 mM EDTA, 0.2% 3-mercaptoethanol (Sigma) and 1000 U/ml of lyticase(Sigma). The mix was incubated at 37° C. for 30 min and fungal genomicDNA was isolated by using QIAamp DNA Stool Mini Kit (Qiagen) accordingto the manufacturer's instructions. For evaluation of fungal rDNA infeces, 80 ng of total fecal DNA was used as a template for qPCRanalysis. The following anti-fungal primers were used:

Target Forward Reverse 18S rDNA (SEQ. ID. NO.: 1)5′-ATTGGAGGGCAAGTCTGGTG-3; (SEQ. ID. NO.: 2) 5′-CCGATCCCTAGTCGGCATAG-3′ITS1-2 (SEQ. ID. NO.: 3) 5′-CTTGGTCATTTAGAGGAAGTAA-3; (SEQ. ID. NO.: 4)5′-GCTGCGTTCTTCATCGATGC-3′ C. tropicalis (SEQ. ID. NO.: 5)5′-TTTGGTGGCGGGAGCAATCCT-3; (SEQ. ID. NO.: 6)5′-CGATGCGAGAACCAAGAGATCCGT-3′ S. fibuligera (SEQ. ID. NO.: 7)5′-CTGCGCTTAACTGCGCGGTT-3′; (SEQ. ID. NO. 8)5′-TGCGAGAACCAAGAGATCCGTTGC-3′

For detection of mucosa-associated fungi, quantitative PCR was performedon DNA isolated from intestinal mucosa using fungal-specific primerslisted above. Relative quantity was calculated by the ΔCt method andnormalized to the amount of β-actin (actb, for mucosal samples) or tothe weight of the sample and the amount of total DNA used (for the fecalsamples). The following β-actin (actb) primers were used: forward primer5′-ATGACCCAGATCATGTTTGA-3′ (SEQ. ID. NO.: 9) and reverse primer5′-TACGACCAGAGGCATACAG-3′ (SEQ. ID. NO.: 10).

Example 12 Microbiome Sequencing Analysis

Mouse fungal and bacterial microbiomes were interrogated using Roche 454and an Illumina GAIIxe next generation sequencing platforms. DNA wasisolated from feces of co-housed or littermate mice before and after DSStreatment, and from a sample of food (Mouse Diet 5015; LabDiet, St.Louis, Mo.) using the protocol described above. 454 library generationand sequencing Fungal ITS1-2 regions were amplified by PCR using primersmodified to include sample barcodes and sequencing adaptors. DNA wasamplified using the following PCR protocol: Initial denaturation at 94°C. for 10 min, followed by 40 cycles of denaturation at 94° C. for 30 s,annealing at 55° C. for 30 s, and elongation at 72° C. for 2 min,followed by an elongation step at 72° C. for 30 min. The PCR productscontaining ITS fungal regions were purified and subjected to emulsionPCR and pyrosequencing using a 454 GS FLX System (Roche DiagnosticsGmbH/454 Life Sciences Corporation) at the UCLA Genotyping andSequencing Core. Fecal DNA was amplified using the PCR protocoldescribed above using the following primers:

Amplicon Forward Reverse ITS1-2 5′-CTTGGTCATTITAGAGGAAGTAA-3′ (SEQ. ID.NO.: 11); 5′-GCTGCGTTCTTCATCGATGC-3′ (SEQ. ID. NO.: 12); 16S (8F&R357)5′-AGAGTTTGATCMTGGCTCAG-3 (SEQ. ID. NO.: 13); 5′-CTGCTGCCTYCCGTA-3′(SEQ. ID. NO.: 14) ITS1-2 and Bacterial 16S amplicons were subjected toa modified TruSeq protocol (version 2). Unique duplexed primerscontaining paired end adapters and indexes were ligated to the 1 μg ofITS1-2 or 16S amplicons respectively. Library enrichment was performedwith 10 cycles of PCR and purification was performed using AgencourtAmpure Magnetic Beads (Beckman). All libraries were subjected to qualitycontrol using qPCR, DNA 1000 Bioanalyzer (Agilent), and Qubit (LifeTechnologies) to validate and quantitate library construction prior topreparing a Paired End flow cell. Samples were randomly divided amongflow cells to minimize sequencing bias. Clonal bridge amplification(Illumina) was performed using a cBot (Illumina). 100×150 bpsequencing-by-synthesis was performed. At 150 bps, 89% of bps were aboveQ30, exceeding Illumina's standard sequence quality metric.

Example 13 Data Analysis

454 data analysis: Raw sequence data were identified by their uniquebarcodes for each dataset and tabulated using QIIME; Unlike bacteria,the range of sequence divergence both between and within species offungi may differ <3% in ITS-2 sequence, approaching the error rate ofthe 454 and making the delineation of sequence reads into OTUs lessprecise. To avoid spurious OTU clustering using 454 data, the inventorsused an alternate approach to defining OTUs in which each uniquesequence read was aligned to a previously described fungal ITS referencedatabase using BLAST. A custom perl script was then used to parse thealignment results to identify alignments with >98% identity over theentire sequence read. Reads failing to align at this stringent levelwere discarded. The alignment results were then tabulated across allreads, using the accession identifier of the ITS reference sequences assurrogate OTUs. Over 85% of the sequences aligned with at least 98%identity to a reference sequence, which corresponds well to both the 98%mapping cut-off previously used in the analysis of the fungal mycobiomeand to the inventors' own analysis of the complete dataset. Finally, theOTUs were manually curated to establish species names.

For Illumina bacterial and fungal analysis, because of the abundance ofIllumina reads and higher overall sequence quality of the reads, theinventors used the QIIM E package with minimal customization. Bcl fileswere de-multiplexed using cassava (v1.8). qSeq files were converted toFASTA files for QIIME using SAMTOOLS (12). QIIME was installed on a 400node dual processor high performance cluster each with 4 GB of RAM. Each150 bp fungal sequence was then BLASTed against the reference databaseusing blastn and a cut off for a 99% nt identity match (>148/150 bps).Each result was summed across unique genbank accession numbers. Forbacterial biome analysis, 150 bp single end reads from each sample werecollapsed into OTUs using UCLUST and annotated.

Example 14 Rarefaction Curves

Using QIIME the inventors performed rarefaction analysis. The originalOTU table was randomly subsampled (rarefied) to create a series ofsubsampled OTU tables. Alpha diversity was calculated on each sampleusing the OTU table and a variety of metrics (PD whole tree, observedspecies, etc). The results of the alpha diversity were collated into asingle file and the number of species identified for each sample versusthe depth of subsampling was plotted.

Example 15 Phylogenic Analysis

Multiple alignments were created for OTU sequences that were found inmurine feces or in the mouse food. Sequences were obtained using theaccession numbers in the dendrograms. Multiple alignments were performedon these sequences using Clustal W2 with a GAP open penalty of 5 and gapextension penalty of 1. Distances from the multiple alignments were thenanalyzed using Unweighted Pair Group Method with Arithmetic Mean (UPGMA)clustering creating dendrograms which were populated at each node withthe distance between each pair wise relationship.

Example 16 Real Time PCR

Tissue samples from the proximal and distal colon were isolated andhomogenized. RNA was isolated by using RNeasy Mini Kit (Qiagen) andreverse transcribed. Real-time RT-PCR analyses were done on the AppliedBiosystems 7500 Fast Real-Time PCR System with the SYBR Green PCR kit asinstructed by the manufacturer (Applied Biosystems). The amount of mRNAwas normalized to the amount of rpl32 mRNA, a housekeeping control genethat does not change substantially during gut inflammation which we havepreviously used for this purpose. Samples were analyzed for geneexpression using the following primers:

Gene Forward Reverse: rpl32 (SEQ. ID. NO.: 15) 5′-AAGCGAAACTGGCGGAAAC-3;(SEQ. ID. NO.: 16) 5′-TAACCGATGTTGGGCATCAG-3′; Il23a (SEQ. ID. NO.: 17)5′-GAACAAGATGCTGGATTGCAGAG-3; (SEQ. ID. NO.: 18)5′-TGTGCGTTCCAGGCTAGCA-3′; Il17a (SEQ. ID. NO.: 19)5′-CAGGACGCGCAAACATGA-3′; (SEQ. ID. NO.: 20)5′-GCAACACTCATCAGAGACACAGAT-3′; Tnfa (SEQ. ID. NO.: 21)5′-TCCAGGCGGTGCCTATGT-3′; (SEQ. ID. NO.: 22)5′-CACCCCGAAGTTCAGTAGACAGA-3′; deja3-defa6 (SEQ. ID. NO.: 23)5′-TCCTCCTCTCTGCCCTYGTCCTG-3′; (SEQ. ID. NO.: 24)5′-AGACACAGCCTGGTCSTCTTCC-3′; cxcl2 (SEQ. ID. NO.: 25)5′-AACATCCAGAGCTTGAGTGTGA-3′; (SEQ. ID. NO.: 26)5′-TTCAGGGTCAAGGCAAACTT-3′.

Example 17 Statistics

Unpaired-Student's t-test was used to evaluate differences betweenexperimental groups. Multiple groups (4-10 mice/group) were analyzed byone way analysis of variance (one way ANOVA) followed by a Tukeymultiple comparisons test. Statistical analysis was performed usingGraphPad Prism software (Graphpad Software Inc., San Diego, Calif.).

Example 18 Study of Medically Refractory Ulcerative Colitis

Ulcerative colitis subjects were recruited at the Inflammatory BowelDisease Center at Cedars-Sinai Medical Center following informed patientconsent and Cedars Sinai-Medical Center Institutional Review Boardapproval. Details of UC diagnosis was based on standard clinical,endoscopic, and histological findings; details have been previouslydescribed along with details of the definition of medically refractoryulcerative colitis (MRUC). In brief, MRUC subjects required colectomyfor severe disease refractory to medical therapies. For the MRUC group,time from diagnosis to date of colectomy was obtained; for the non-MRUCgroup time from diagnosis to last follow-up visit was obtained.Demographics for these subjects have been previously published; ingeneral the median follow-up of the non-MRUC group was twice that oftime to colectomy of the MRUC group. Healthy controls were obtained fromthe Cardiovascular Health Study (CHS), a population-based cohort studyof risk factors for cardiovascular disease and stroke in adults 65 yearsof age or older, recruited at four field centers 5,201 predominantlyCaucasian individuals were recruited in 1989-1990 from random samples ofMedicare eligibility lists, followed by an additional 687African-Americans recruited in 1992-1993 (total n=5,888). CHS wasapproved by the Institutional Review Board at each recruitment site, andsubjects provided informed consent for the use of their geneticinformation. A total of 3208 Caucasian non-IBD control subjects whounderwent GWAS were included in these analyses. African-American CHSparticipants were excluded from analysis due to insufficient number ofethnically-matched cases. Genotyping was performed at the MedicalGenetics Institute at Cedars-Sinai Medical Center using the IlluminaHumanCNV370 platform (Illumina, San Diego, Calif.). Five SNPs passingquality control spanned the CLEC74 gene (FIG. 24A); a total of 806 UCsubjects with complete CLEC7A genotyping data, MRUC determination, andtime to surgery or to last visit and were included in these analyses(MRUC n=315; non-MRUC n=491). The rs2078178 (SEQ. ID. NO.:27)-rs16910631 (SEQ. ID. NO.: 28) haplotype was identified by loadingthe SNP data into Haploview v4 and testing for association (FIG. 24B).Assignment of haplotypes for final analysis employed PHASE v2.3. Thenumber of each haplotype assigned is as follows:

Haplotype number assigned

1 AG 430

2 AA 45

3 GG 1314

4 GA 43

The greatest uncertainty in the assignment was when the subject washeterozygous for both markers. These were removed from the analysis.Haplotypes formed with probability >0.99 were tested for associationwith MRUC by logistic regression and Fisher's Exact Test, and forassociation with time to surgery by fitting with a Cox proportionalhazards model (Survival package in R). Haplotypes listed as “Othercombinations” were those that could not be reliably determined(posterior p<0.95). These were not included in the logistic regressionor Cox proportional hazards analyses.

While the description above refers to particular embodiments of thepresent invention, it should be readily apparent to people of ordinaryskill in the art that a number of modifications may be made withoutdeparting from the spirit thereof. The presently disclosed embodimentsare, therefore, to be considered in all respects as illustrative and notrestrictive.

The various methods and techniques described above provide a number ofways to carry out the invention. Of course, it is to be understood thatnot necessarily all objectives or advantages described may be achievedin accordance with any particular embodiment described herein. Thus, forexample, those skilled in the art will recognize that the methods can beperformed in a manner that achieves or optimizes one advantage or groupof advantages as taught herein without necessarily achieving otherobjectives or advantages as may be taught or suggested herein. A varietyof advantageous and disadvantageous alternatives are mentioned herein.It is to be understood that some preferred embodiments specificallyinclude one, another, or several advantageous features, while othersspecifically exclude one, another, or several disadvantageous features,while still others specifically mitigate a present disadvantageousfeature by inclusion of one, another, or several advantageous features.

Furthermore, the skilled artisan will recognize the applicability ofvarious features from different embodiments. Similarly, the variouselements, features and steps discussed above, as well as other knownequivalents for each such element, feature or step, can be mixed andmatched by one of ordinary skill in this art to perform methods inaccordance with principles described herein. Among the various elements,features, and steps some will be specifically included and othersspecifically excluded in diverse embodiments.

Although the invention has been disclosed in the context of certainembodiments and examples, it will be understood by those skilled in theart that the embodiments of the invention extend beyond the specificallydisclosed embodiments to other alternative embodiments and/or uses andmodifications and equivalents thereof.

Many variations and alternative elements have been disclosed inembodiments of the present invention. Still further variations andalternate elements will be apparent to one of skill in the art. Amongthese variations, without limitation, are the selection of constituentmodules for the inventive compositions, and the diseases and otherclinical conditions that may be diagnosed, prognosed or treatedtherewith. Various embodiments of the invention can specifically includeor exclude any of these variations or elements.

In some embodiments, the numbers expressing quantities of ingredients,properties such as concentration, reaction conditions, and so forth,used to describe and claim certain embodiments of the invention are tobe understood as being modified in some instances by the term “about.”Accordingly, in some embodiments, the numerical parameters set forth inthe written description and attached claims are approximations that canvary depending upon the desired properties sought to be obtained by aparticular embodiment. In some embodiments, the numerical parametersshould be construed in light of the number of reported significantdigits and by applying ordinary rounding techniques. Notwithstandingthat the numerical ranges and parameters setting forth the broad scopeof some embodiments of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspracticable. The numerical values presented in some embodiments of theinvention may contain certain errors necessarily resulting from thestandard deviation found in their respective testing measurements.

In some embodiments, the terms “a” and “an” and “the” and similarreferences used in the context of describing a particular embodiment ofthe invention (especially in the context of certain of the followingclaims) can be construed to cover both the singular and the plural. Therecitation of ranges of values herein is merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range. Unless otherwise indicated herein, eachindividual value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g. “such as”) provided with respectto certain embodiments herein is intended merely to better illuminatethe invention and does not pose a limitation on the scope of theinvention otherwise claimed. No language in the specification should beconstrued as indicating any non-claimed element essential to thepractice of the invention.

Groupings of alternative elements or embodiments of the inventiondisclosed herein are not to be construed as limitations. Each groupmember can be referred to and claimed individually or in any combinationwith other members of the group or other elements found herein. One ormore members of a group can be included in, or deleted from, a group forreasons of convenience and/or patentability. When any such inclusion ordeletion occurs, the specification is herein deemed to contain the groupas modified thus fulfilling the written description of all Markushgroups used in the appended claims.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention.Variations on those preferred embodiments will become apparent to thoseof ordinary skill in the art upon reading the foregoing description. Itis contemplated that skilled artisans can employ such variations asappropriate, and the invention can be practiced otherwise thanspecifically described herein. Accordingly, many embodiments of thisinvention include all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

Furthermore, numerous references have been made to patents and printedpublications throughout this specification. Each of the above citedreferences and printed publications are herein individually incorporatedby reference in their entirety.

In closing, it is to be understood that the embodiments of the inventiondisclosed herein are illustrative of the principles of the presentinvention. Other modifications that can be employed can be within thescope of the invention. Thus, by way of example, but not of limitation,alternative configurations of the present invention can be utilized inaccordance with the teachings herein. Accordingly, embodiments of thepresent invention are not limited to that precisely as shown anddescribed.

The invention claimed is:
 1. A method of diagnosing susceptibility to inflammatory bowel disease (IBD) in a subject, and treating said subject, comprising: obtaining a sample from the subject; subjecting the sample to a genotyping assay adapted to determine the presence or absence of one or more risk variants at the Dectin-1 gene (CLEC7A), wherein the genotyping assay comprises using quantitative polymerase chain reaction (qPCR), and wherein the one or more risk variants comprises rs2078178 (SEQ ID NO: 27), rs16910631 (SEQ ID NO: 28) or a combination thereof; diagnosing susceptibility to IBD in the subject based on the presence of one or more risk variants at the Dectin-1 gene (CLEC7A); and administering an anti-fungal drug to the subject.
 2. The method of claim 1, wherein IBD is a severe form of ulcerative colitis.
 3. The method of claim 1, wherein IBD is based on the inability to control fungi in the gut of the individual.
 4. The method of claim 1, wherein the anti-fungal drug is fluconazole.
 5. The method of claim 1, wherein IBD is medically refractory ulcerative colitis (MRUC). 